This invention relates to methods and apparatus for inflating and sealing pillows in packaging.
This invention relates particularly to the construction and operation of a machine which is small enough to be installed for operation on site where articles packaged for transport are placed in shipping containers with protective inflated pillow-type strip packaging.
This invention relates particularly to a machine which is compact in overall size, which can be conveniently operated to produce varied lengths of strips of inflated pillow-type packaging as needed, which can begin production of inflated pillow-type strip packaging immediately after being held out of a production cycle for some period of time and which applies a heated sealing element directly to and in sliding contact with a web of film to securely seal the inlet port of an inflated pillow while the pillow is under pressure and as the web of film is continuously and uninterruptedly advanced through the machine.
This invention relates particularly to a machine which forms the seal complete and secure during a short path of travel and during a short interval of time. The seal is made without the need for additional pressing together of the film after the sealing and without the need for additional cooling of the seal after the sealed inlet port moves out of contact with the sealing structure.
Webs of plastic film which are constructed to permit the production of strips of air filled envelopes, cushions and pillows have (in the past ten years or so) been used extensively for cushioning objects to be transported in containers.
The thin webs of plastic film are inexpensive, tough, resilient and recyclable. Strips of inflated pillow packaging which are created from these webs of plastic film are used for void-fill packaging to replace products such as crumpled paper or polystyrene peanuts and for protective packaging to replace molded or extruded foams.
U.S. Pat. Nos. 5,454,642; 5,651,237; 5,755,328; 4,017,351; and 5,824,392 disclose methods, apparatus, and webs of plastic film used for making strips of inflated pillow packaging of this general kind. Each of these U.S. patents is incorporated by reference in this application.
U.S. Pat. Nos. 6,116,600 and 6,209,286 also disclose methods, apparatus and webs of plastic film of this general kind and are incorporated herein by reference.
Sealing an inflated pillow made a web of plastic film while the air inflates the pillow under pressure and while the web of plastic film is being transported through the machine presents problems.
The seal must be secure and must not leak in order for the inflated pillow packaging to be used effectively for cushioning objects transported within a container.
The seal needs to be formed efficiently, quickly and without extensive, related pressing and/or cooling structure in order to make the machine as compact as possible in size and as efficient as possible in production rate.
To simplify machine construction and to provide a high efficiency of production, it is desirable to be able to make the seal as the web of plastic film is moved continuously and without any interruption and/or intermittent stopping of the film transport during the sealing operation.
It is a primary object of the present invention to construct and to operate a machine which is compact in size, which is efficient in production, which is continuous and uninterrupted in operation and which produces seals which are secure and which do not leak.